Recently, a new system for culturing primary tissues in a three-dimensional configuration has been constructed in this laboratory. The system involves an artificial porous stroma for the cells and a system of artificial capillaries through which nutrients and oxygen are supplied to the tissues. It is proposed that the effects on cultured tissues of several variables of the system should be studied. The variables include oxygen levels, the rates of flow of the culture medium through the capillaries, density of distribution of the capillaries in the porous matrix, and composition of the culture medium. Further extension and improvement of the system is intended. This part of the work will depend greatly on obtaining supplemental funds for a research associate. In addition, research will be started on the development of an epithelial lining on the substrate of connective tissue cultured on porous matrix.